Everything the show did well:
-The show first half is really great overall. Most characters are likable during that period, and the general tone and atmosphere feels great.
-Episode 42 was amazing.
-Pretty good finale.
-Daiji's actor is great and has excellent delivery for his scenes.
-Lovekov is a pretty loveable mascot.
-The action in the first half, excluding the CGI forms, is really well done and different from other shows as it feels like controlled chaos.
-The music in the first half is among the franchise's most unique.
-The first quarter of the show has more budget than usual.

Everything the show did bad:
-The mysteries and character arcs setup in the show's first half get resolved either boringly or just straight up bad.
-By the end of the show barely any character remains likeable and the ones that do aren't really anything impressive, just 'good'.
-The main protagonist Ikki is a very boring character overall, and his partner Vice doesn't really feel like a co-protagonist and just feels like a mascot. Their character arc is only interesting in the finale. Ikki in the beginning is busybody type character and has good detective skills but by the second half he stops doing any of this for the most part, while letting his siblings resolve their own problems is unique it barely gives him a chance to develop character.
-Daiji is the worst part of the first arc because his rivalry with Ikki feels repetitive, that isn't much of an issue and he remains pretty likeable during the first half but after he obtains his upgrade Holy Live his character just keeps getting worse. Most of his actions in the second half stem from fear of the main antagonist but said antagonist doesn't come off powerful enough which makes most of his decisions feel nonsensical. Also the rest of the cast are jerks to him for seemingly no reason.
-Sakura is really likeable before becoming a rider, but once she does she becomes a brat. This would be fine since they're clearly setting up her developming maturity after being smug and in the first arc they manage to make some interesting things with this. However the show despite her barely winning any battles and being a smug brat who has yet to know her place, almost every character sucks her off as if she's somehow amazing. When it's time to resolve her arc it happens mostly off-screen which feels like a cop-out.
-The main antagonist Giff is only likeable when he was a statue. Once he becomes a proper monster he loses all of his personality and his actual plan is really dumb.
-Julio and Aguilera become joke characters with barely any direction after episode 18.
-Most of George character arc in the second half feels forced and contradictory to his personality in the first half.
-Hiromi, Genta, Bu-san, Kagero and Olteca remain the most likeable characters because they remain mostly absent in the second half where the show went bad and you bet that when they appear later in the second half the show tries its best to ruin them.
-The action degrades heavily in the second half for several reasons. There's barely any new enemies and they mostly spend fighting Veil and Giffdemos, the new riders introduced barely have any character at all so they don't have an interesting moveset and the powers the main cast get from their upgrades feel detached from the initial themes.
-For the second half of the show they mostly use more generic sounding action music or old tracks from the first half. All new tracks that are actually unique get barely used.
-The eviction plot-line gets forgotten.
-The shot in the opening of the main protagonist in a flaming school never happens in the show, it's the only time that I can think of in the franchise were the show opening seeminly hinting at a plot point goes nowhere.
-One of the worst final arcs in the franchise.
-The show is worse on a re-watch since now you know that the mysteries and set up aren't actually building up to anything.
-Weird anti-vaccine message episode.
-The show does a poor job at making the main antagonist Giff feel powerful or even menacing.

Reasons for the show strenghts:
Producer Mochizuki has ton of interesting ideas, good set of directors.

Reasons for the show flaws:
Producer Mochizuki puts all of his good ideas in the first quarter which makes it feel kinda cluttered and also makes him go overbudget. After the first quarter he pretty much gives the main writer complete freedom. Keep in mind this is the same strategy he used in his previous show Kyuranger which resulted in him being demoted, he was promoted again and given a second chance since it have been a long time since that show, but this shows he pretty much didn't learn anything, which resulted in him getting demoted again inmediately after the show ended.
The writer who gave complete freedom, Hanta Kinoshita, didn't really care for any of Mochizuki's ideas nor actually likes Kamen Rider, he's more of marvel comic fans. After the first quarter he pretty much retconned everything Mochizuki and director Shibasaki had set up without any actual planning. He publicly admitted that he didn't have anything planned for the main protagonist duo nor the deadmans past episode 18 and had nothing planned for Daiji past episode 27. His only focus pretty much was Sakura and Weekend. All of these decisions made him ruin the show's second half with the exception of episode 42. It legimetely seems that he was angry that his idea of a female protagonist was rejected and that Hiromi, a character that was supposed to die in the first episode before the script being changed because the staff liked the actor, ended up being more popular than Sakura and Vice. Kinoshita also inserted his own political views into the show. The writer just generally comes off as petty.
Besides that, the character Hikaru who had barely done anything suddenly changing and becoming prominent in the second half despite having no personality, is heavily speculated to have happened due to him being from a profilic agency and that the staff was forced to give him more screen time.
Due to Sakura being so poorly written and her arc being resolved off-screen despite the writer's insistance that she's his favorite character one has to assume that something that we're not aware of happened in production.

Overall:
If you care about consistency this will most likely be an average show due to the first half being really great and the second being really bad. If you care about writing quality this is easily one of the franchise's worst. One cannot really get a feel for the characters and story by watching the first 3 episodes due to how much the show changes. I honestly cannot really recommend this show when the tokusatsu genre has other much better titles.
Personally since my biggest draw to shows are characters, this is the worst Rider show I've seen so far. In Wizard Haruto, Nitou and Gremlin at least were really likeable. In Ghost Alain was amazing, only the 2 dudes from the temple were boring, and Chikara and Adel were really bad, but otherwise the cast was enjoyable. Zi-O had Woz being really fun, and while the character writing was heavily inconsistent they at least were entertaining and had some interesting concepts done well. Revice really has none of that going for it.